Date: Mon, 27 May 2013 10:31:14 +0100 From: Andrew Turner <andrew@fubar.geek.nz> To: Tim Kientzle <kientzle@freebsd.org> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Git crash on EABI system. Message-ID: <20130527103114.3fbb00fb@bender.Home> In-Reply-To: <2290084B-D302-4489-BB01-817497901E2B@freebsd.org> References: <A44A52E5-E878-45CD-B032-F111E5E244BA@freebsd.org> <51949698.80205@thieprojects.ch> <2290084B-D302-4489-BB01-817497901E2B@freebsd.org>
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[-- Attachment #1 --]
On Thu, 16 May 2013 05:04:29 -0400
Tim Kientzle <kientzle@freebsd.org> wrote:
>
> On May 16, 2013, at 4:19 AM, Werner Thie wrote:
>
> >> Has anyone else seen this from git on a clang/EABI system?
> >>
> >> Assertion failed: (attr_stack->origin), function
> >> prepare_attr_stack, file attr.c, line 630.
> >>
> >> Program received signal SIGABRT, Aborted.
> >> [Switching to Thread 20c03300 (LWP 100076/git)]
> >> 0x204b842c in thr_kill () from /lib/libc.so.7
> >> (gdb) bt
> >> #0 0x204b842c in thr_kill () from /lib/libc.so.7
> >> #1 0x2044157c in raise () from /lib/libthr.so.3
> >> #2 0x20598130 in abort () from /lib/libc.so.7
> >> #3 0x20574630 in __assert () from /lib/libc.so.7
> >> #4 0x00076b28 in ?? ()
> >>
> >> I'm planning to do a debug build and see if I can track down any
> >> more details.
> >
> > Hi Tim
> >
> > just built git out of curiosity after your post on the BBone
> >
> > FreeBSD beaglebone 10.0-CURRENT FreeBSD 10.0-CURRENT #0 r250144M:
> > Sat May 4 14:18:20 CEST 2013
> > root@xtools:/usr/home/wthie/proj/crochet-freebsd/work/obj/arm.armv6/usr/local/src/sys/BEAGLEBONE-NOWITNESS
> > arm
> >
> > git crashes exactly as advertised when cloning a project in
> >
> > Assertion failed: (attr_stack->origin), function
> > prepare_attr_stack, file attr.c, line 630.
>
> Thanks for verifying that.
>
> Unfortunately, a debug build (make -DWITH_DEBUG) does
> not crash for me. So I clearly have more work ahead of me
> to narrow this down.
Hello Tim,
Can you test the attached patch for llvm. It should fix git to not
crash. The patch is llvm r180609 [1].
The issue was llvm failed to correctly account for pre-indexed
loads/stores. It would then use a subtraction to get the correct
address of the last slash however it used the wrong subtract
instruction.
Andrew
[1] http://llvm.org/viewvc/llvm-project?view=revision&revision=180609
[-- Attachment #2 --]
Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp (revision 180608)
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp (revision 180609)
@@ -7152,25 +7152,40 @@
assert(OtherUses[i]->getOperand(!OffsetIdx).getNode() ==
BasePtr.getNode() && "Expected BasePtr operand");
- APInt OV =
- cast<ConstantSDNode>(Offset)->getAPIntValue();
- if (AM == ISD::PRE_DEC)
- OV = -OV;
+ // We need to replace ptr0 in the following expression:
+ // x0 * offset0 + y0 * ptr0 = t0
+ // knowing that
+ // x1 * offset1 + y1 * ptr0 = t1 (the indexed load/store)
+ //
+ // where x0, x1, y0 and y1 in {-1, 1} are given by the types of the
+ // indexed load/store and the expresion that needs to be re-written.
+ //
+ // Therefore, we have:
+ // t0 = (x0 * offset0 - x1 * y0 * y1 *offset1) + (y0 * y1) * t1
ConstantSDNode *CN =
cast<ConstantSDNode>(OtherUses[i]->getOperand(OffsetIdx));
- APInt CNV = CN->getAPIntValue();
- if (OtherUses[i]->getOpcode() == ISD::SUB && OffsetIdx == 1)
- CNV += OV;
- else
- CNV -= OV;
+ int X0, X1, Y0, Y1;
+ APInt Offset0 = CN->getAPIntValue();
+ APInt Offset1 = cast<ConstantSDNode>(Offset)->getAPIntValue();
- SDValue NewOp1 = Result.getValue(isLoad ? 1 : 0);
- SDValue NewOp2 = DAG.getConstant(CNV, CN->getValueType(0));
- if (OffsetIdx == 0)
- std::swap(NewOp1, NewOp2);
+ X0 = (OtherUses[i]->getOpcode() == ISD::SUB && OffsetIdx == 1) ? -1 : 1;
+ Y0 = (OtherUses[i]->getOpcode() == ISD::SUB && OffsetIdx == 0) ? -1 : 1;
+ X1 = (AM == ISD::PRE_DEC && !Swapped) ? -1 : 1;
+ Y1 = (AM == ISD::PRE_DEC && Swapped) ? -1 : 1;
- SDValue NewUse = DAG.getNode(OtherUses[i]->getOpcode(),
+ unsigned Opcode = (Y0 * Y1 < 0) ? ISD::SUB : ISD::ADD;
+
+ APInt CNV = Offset0;
+ if (X0 < 0) CNV = -CNV;
+ if (X1 * Y0 * Y1 < 0) CNV = CNV + Offset1;
+ else CNV = CNV - Offset1;
+
+ // We can now generate the new expression.
+ SDValue NewOp1 = DAG.getConstant(CNV, CN->getValueType(0));
+ SDValue NewOp2 = Result.getValue(isLoad ? 1 : 0);
+
+ SDValue NewUse = DAG.getNode(Opcode,
OtherUses[i]->getDebugLoc(),
OtherUses[i]->getValueType(0), NewOp1, NewOp2);
DAG.ReplaceAllUsesOfValueWith(SDValue(OtherUses[i], 0), NewUse);
help
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